1. Field of the Invention
The present invention relates to a coupling device for circular pipes, and more particularly to a coupling device for circular pipes, in which a pair of locking rings is arranged to clamp a circular pipe and a body for receiving the circular pipe is configured to press a packing in order to ensure a seal.
2. Description of the Related Art
As well known in the art, in a conventional coupling device for circular pipes, a packing, a support ring and a locking ring are inserted sequentially into a body, and a nut having an entrance hole is engaged with the body so that the packing maintains a seal and the locking ring clamps a circular pipe. With the circular pipe inserted into the coupling device through the entrance hole, the locking ring exerts a locking force on the circular pipe so that it is not separated from the coupling device even if an external force is applied in a direction opposite to a direction of inserting the circular pipe.
In a coupling device having this structure, the packing is simply inserted into and coupled with the body. Accordingly, after the circular pipe is inserted into and coupled with the body of the coupling device, in the case where contents flowing through the connecting device leak from the coupling device or the circular pipe is not correctly inserted in a horizontal position, it becomes necessary to separate the circular pipe from the coupling device. However, in order to separate the circular pipe, it is required to break the body of the coupling device or cut the circular pipe.
For these reasons, the conventional coupling device for circular pipes can be used only by skilled persons.
Furthermore, conventional circular copper pipes, which have been widely used, are being replaced by stainless corrugated pipes these days. Accordingly, in some cases, it is efficient to replace a conventional circular pipe with a corrugated pipe. However, no means for connecting the circular pipe with the corrugated pipe has been devised.